1. Field of the Invention
The present invention generally relates to transparent plastic panels for use in automobiles and other structures and more particularly, to window assemblies for the same.
2. Description of the Known Technology
Plastic materials, such as polycarbonate (PC) and polymethyl methyacrylate (PMMA), are currently being used in the manufacturing of numerous automotive parts and components, such as B-pillars, headlamps, and sunroofs. Automotive window modules represent an emerging application for these plastic materials because of various advantages in the areas of styling/design, weight savings, and safety/security. More specifically, plastic materials offer the automotive manufacturer the ability to reduce the complexity of the window assembly through the integration of functional components into the molded plastic module, as well as to distinguish their vehicle from a competitor's vehicle by increasing overall design and shape complexity. The use of light weight plastic window modules may facilitate both a lower center of gravity for the vehicle and improved fuel economy. Additionally, plastic window modules increase the overall safety of a vehicle by enhancing the retention of occupants during a rollover accident.
However, plastic window modules, like their glass counterparts, may allow significant amounts of solar energy into the occupant compartment of the automobile. If a prolonged period of time passes without any form of cooling, the occupant compartment of the automobile may become uncomfortable. Furthermore, even if a cooling system is provided to cool the occupant compartment, use of the cooling system will result in an increased load on the vehicle, possibly lowering the fuel economy of the automobile.
One way of limiting the introduction of solar energy into the passenger compartment of the vehicle is by tinting the window module, thereby only allowing a portion of sunlight through the window module. However, on less sunny days, a tinted window module has the drawback of excessively darkening the occupant compartment of the automobile and may impede the ability of the occupants to clearly see objects through the window module.
Therefore, it is desired to provide a plastic window module capable of limiting solar energy introduced into the occupant compartment of the automobile without impeding the vision of the occupants on less sunny days.